Method of weaving



United States PatentO METHOD OF WEAVING Svend Sigurd Christie Fleischer,Charlottenlund, and Christen Carl Thomsen, Hellerup, Denmark.

No Drawing. Application December 4, 1950, Serial No. 199,148

Claims priority, application Denmark December 10, 1949 8 Claims. (Cl.139-1) that the fabric will have a tendency to shrink in the direc-'tion of the weft, particularly along the edges of the woven fabric, sothat the width of the finished goods will be less than the width of thewarp in the reed. The reason is that the weft thread is introduced inthe shed in stretched.

or almost stretched condition and therefore can bend around the warpthreads only by a reduction in the width of the fabric. This difficultyhas to some extent been overcome by attempts made to keep the weftthreads stretched also in the fabric and to force the warp threads tobend around the weft. This has been done, for instance, by employing atboth sides of the fabric one or more stretcher-s according to thequality of the goods, but these stretchers are cumbersome in use and mayspoil the fabric by spreading the warp threads excessively in places sothat the woven fabric will show holes or irregularities. Besides, suchstretchers are not sufiiciently effective in the case of goods in whichconsiderable warp tension is required. Also in these cases difficultieshave in respect of certain fabrics been overcome by the use of inelasticweft threads of, for instance, jute, flax or heavily sized threadsresisting bending. Such weft threads will, however, in many casesdepreciate the quality of the goods.

Shrinking in the direction of the .weft may also be avoided if the weftthread is entered in the shed with so much excess length distributedover its entire width that the length of thread will be just sufiicientto allow the weft to bend around the taut warp threads.

This method has been used, for instance, in the case of certainhandwoven fabrics, when the weft thread is laid in large or small loopsin the shed before being woven in. In the case of power looms this will,however, be a very difiicult process requiring much time and reducingthe output considerably. It will likewise be difiicult toobtain aregular distribution of the lengths of thread, so that in many casesloose and firm parts will alternate in the fabric.

These difficulties are obviated by the present invention which relatesto the use of a weft thread the excess length of which has been producedbeforehand.

The characteristic feature of the invention consists in the use as aweft thread of stretchable yarns introduced in the shed unstretched andthen stretched during or after, and preferably immediately after theweaving in of the weft into the fabric.

According to the invention the stretchable weft thread used may bethreads bent together or coiled in stretchable bundles, spirals, loopsor the like shapes, and which in such shape are so fixed that they maybe introduced in the shed without being'stretched materially and then bestretched after introduction in the shed. One-ply or multi-ply, spun orunspun yarns may be used as weft threads.

According to the invention weft threads may be fixed in unstretchedcondition by being twisted together with one 2,723,683 Patented Nov. 15,1955 or more, preferably thin, binder threads. If, for instance, twobinder threads are used, one may be twisted clockwise and the otheranti-clockwise on the weft so that one binder thread will hold theother. The binder threads should preferably be placed tightly around theweft so as to keep it in the shapes mentioned. According to theinvention fragile, to some extent inelastic binder threads may be used.Such threads which possess considerably less breaking strength than theactual weft thread will relatively easily be broken'during the weaving,as described in more detail in the following. By the breaking of thebinder thread the fixing of the weft thread will be released so that theweft thread may be extended to its full length. According to theinvention it may as an alternative be expedient to use binder threadshaving only slight or practically no elastic elongation and thereafter agreater inelastic elongation. Also such binder threads will release thefixing of the weft by their great inelastic elongation. By way of anexample may be mentioned cellulose acetate threads which like certainother threads possess the property that when exposed to tension theyfirst give slight elastic elongation but thereafter a greater inelasticelongation. Threads of this kind are especially suitable for the presentpurpose.

According to the invention the weft threads may also be fixed bybeingtwined with binder threads of more or less plastic substances,preferably such as do not become plastic' until the temperature issomewhat increased. Thus, artificial thread may be used which in itselfbecomes lastingly elongated or which becomes so at light heating, forinstance certain kinds of nylon thread. During or after weaving suchartificial threads may be made to stretch, whereby the fixing of theweft thread will be released.

Further, the weft threads may according to the invention be fixed inunstretched condition by impregnation or surface treatment with more orless brittle or fragile agents. The weft threads may, for instance, befixed by means of lacquers, water glues or starches, or they may beglued to a suitable strip of, for instance, paper. During or after theweaving such agents may be broken so that'the weft thread may bestretched.

According to the invention weft threads may be used fixed both by binderthreads and by means of impregnation or surface treatment.

In order to facilitate the stretching of the fixed weft threads it willaccording to the invention in many cases be expedient to use fixingagents that may be weakened by special means. Such means may be appliedbefore, during or after the weaving either to the full extent of theweft thread or at intervals.

If fixing media are used which may be weakened by moistening with water,as will, for example, be the case of binder threads of certain fibres,such as various kinds of synthetic wool or some impregnation or surfacetreatment media, it may be expedient to use moistening with water, ifnecessary in conjunction with the use of agents reducing its surfacetension. The fixing medium will thereby be weakened to such an extent asto facilitate the stretching of the weft thread by breaking, elongationor bursting of the fixing medium.

If fixing media are used which may be weakened or dissolved by treatmentwith certain substances, they may be treated with such substances, forinstance organic solvents or chemicals. Thus, alginate threads may betreated with alkalines, such as soap, and cellulose acetate threads withorganic solvents, for instance, acetone. The same rule applies to weftthreads impregnated or surface treated with such substances.

For the weakening it will further be possible to use heating as statedby way of an example in the foregoing in the case of binder threads ofplastic materials. Heating may, however, be used also under othercircumstances, for instance in the case of impregnated or surfacetreated weft threads. Such heating may, for example, take place bycontact with a warm surface, by radiation, by means of high-frequencyapparatus or by steaming.

According to the invention the release of the fixing and thereby thestretching of the weft thread may be promoted, or performed solely, bymechanical means, preferably by means of the reed or special mechanicaldevices connected with the reed. Thus, it is possible to use a battenwhich is introduced in the shed between the weft thread and the edge ofthe fabric and which enters between the lamellae of the reed during theupward motion of the latter, whereby the fixing agent will be broken orelongated. The batten is then removed before the reed has moved the weftall the way up.

According to the invention the stretching of the weft thread may takeplace by separate mechanical means.

In the weaving of certain handwoven goods it is a known practice to usealternately a slack and a taut weft thread, whereby greater density ofthe fabric is attained. A similar effect may be attained by the presentmethod by using alternately taut weft threads and weft threads accordingto the invention. If it is desired, weft threads according to theinvention may be used, some with great and others with small elongation.

Having thus described our invention what we claim is:

1. Method for weaving on a loom of a fabric so as to avoid substantialshrinking thereof in the direction of the weft during weaving,comprising the injection in the shed of a stretchable weft threadmaintained in unstretched condition by binder means and allowing saidthread to be stretched during the weaving operation on the 'loom,thereby rendering the binder means ineffective and the elongation of theweft thread permanent.

2. Method according to claim 1, in which said stretchable weft threadis, prior to introduction into the loom, fixed in curled shape so thatit may be introduced in the shed without material stretching and then isallowed to stretch after introduction in the shed.

3. Method according to claim 1, in which said stretchable thread isfixed in unstretched condition by twining it together with at least onefragile binder thread having a considerably lesser breaking strengththan said stretchable thread, before it is put on the loom.

4. Method according to claim 1, as applied to weaving with a stretchableyarn twined together with at least one fragile binder thread, in whichsaid stretchable thread is fixed both by the binder thread and byembrittling of at least the surface of the stretchable thread.

5. Method according to claim 1, as applied to weaving with a stretchableyarn twined together with at least one fragile binder thread, in whichsaid binder thread is made of a material displaying substantially noelastic elongation and thereupon a greater inelastic elongation.

6. Method according to claim 1, as applied to weaving with a stretchableyarn twined together with at least one fragile binder thread, in whichthe stretchable weft thread is fixed in curled shape so that 'it may beintroduced in the shed without material stretching and then be made tostretch after introduction in the shed and the binder thread is ofplastic material becoming plastic at an increased temperature.

7. Method of weaving with a weft thread containing binder threads, on aloom .a fabric so that during weaving a substantial shrinking in thedirection of the weft is avoided, comprising the use of a stretchableweft thread introduced between the sheds in unstretched condition- .andthereafter stretched, the stretchable weft thread being :fixed in curledshape so that it may be introduced in the shed without materialstretching and then be made :to stretch after introduction in the shed,and in which the binder thread is made of a suitable substance and isweakened by treatment with an agent chosen from the group consisting ofwater, non-aqueous solvents, heat and chemical materials acting uponsaid binder thread,

said group being characterized by a weakening action upon said binderthread, said process being used upon at least a part of the weft thread.

8. Method according to claim 1, as applied to weaving with a stretchablethread, in which said thread is fixed in unstretched condition, and saidbinder means comprises at least one binder thread which is fragile andsubstantially inelastic, and is twined together with said stretchablethread.

References-Cited in the 'file of this patent UNITED STATES PATENTS1,955,582 Golding Apr. 17, 1934 2,017,444 Page Oct. 15, 1935 2,155,213Zenorini Apr. 18, 1939 2,435,543 Johnson et al Feb. 3, 1948 2,592,154Johnson et al. Apr. 8, 1952

